Influence of Sacrificial Cathodic Protection on the Chloride Profile in Concrete

The durability of reinforced concrete structures significantly depends on the condition of the steel embedded in them. Structures exposed to chloride containing environment have reduced durability due to corrosion of the reinforcement steel. Several diffusion models have been proposed for chloride penetration. They mainly aim at predicting the initiation of corrosion of the reinforcement. They are based on diffusion conditions influenced by parameters such as relative humidity, temperature, rains etc. This work presents the influence of sacrificial cathodic protection on the chloride profile in concrete. Cathodic protection to the embedded steel in concrete was established by plugging-in a sacrificial magnesium alloy anode at the center of the slab and providing an electrical link between them. The current flowing between the magnesium anode and the embedded steel was regularly measured. The water soluble chloride content at different distances from the anode and at different times was determined after implementation of cathodic protection. The chloride content decreased at different distances from the anode, with increase in time. The diffusion of chloride occurred at a more accelerated rate due to the flow of cathodic protection current.